1. Field of the Invention
The present invention relates to an image forming apparatus such as a printer which forms a color image by means of superimposition of toner images respectively formed on plural electrostatic latent image carriers.
2. Background Art
As a color image forming apparatus such as a printer or a facsimile apparatus, known is a tandem image forming apparatus in which process units each including: a photosensitive member serving as an electrostatic latent image carrier; a charging device and an exposing device that form an electrostatic latent image on the photosensitive member; and a developing device that develops the electrostatic latent image formed on the photosensitive member by a toner are disposed respectively for colors (for example, four colors of cyan, magenta, yellow, and black), and the color toner images respectively formed on the photosensitive members are transferred so as to be superimposed on one another, thereby forming a color image.
In some of such tandem image forming apparatuses, plural process units are horizontally arranged (for example, see JP-A-10-307439 (Page 4)).
However, such a so-called lateral tandem image forming apparatus has a problem in that the installation area is large. Therefore, a so-called vertical tandem system in which plural process units are vertically arranged so as to reduce the installation area has been proposed.